From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Vehicle suspension performance, damper settings, and road testing methodologies.
| Identifier | ExFiles\Box 55\3\ Scan263 | |
| Date | 29th September 1926 guessed | |
| contd :- -2- in our dampers in England. We attach a specification and viscosity curve. We should rather like you to try out an oil something like this and let us know what affect it has in very cold weather in the States. We think the reason why you get excessive pitching with the R-R hydraulics on the front, is because with a strong upward check action, when the centre of gravity of the car is rising vertically and the front of the car is held, the back of the car will be raised through twice the distance unless some fairly effective rear dampers are fitted. On our recent 10,000 miles car we ran R-R hydraulics at 60 lbs. up and 80 lbs. down on the rear, in conjunction with the front shock dampers at 80 lbs. up and 40 lbs. down. The car held the road at high speeds better than any 40/50 HP. we have previously tested. We are rather puzzled as to the way in which your suspension tests are carried out. Attached is a description of the apparatus used in our standard riding comfort tests at low speeds in the back of the car. The same tests also do for high speeds, if the road is not too bad. It would be rather a help to us if you could construct two or three of the contrivances described, try them in the back of the car and let us have the figures. In all our measurement tests we have been absolutely unable to appreciate the slightest difference in the alteration to the front shackle on the riding of the car at low speeds i.e., the speed at which the majority of our contd :- | ||